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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2016-06-27 14:12:34 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2016-07-20 17:50:23 -0700
commit510cccb5b0c8868a2b302a0ab524da7912da648b (patch)
tree3b56ec2823c7b2757d1dea1c97b3b02a4595f7c4 /drivers
parente4add7b6beaff4061693d0632bc1dcb306edba10 (diff)
downloadlinux-510cccb5b0c8868a2b302a0ab524da7912da648b.tar.gz
linux-510cccb5b0c8868a2b302a0ab524da7912da648b.tar.xz
tty/vt/keyboard: fix OOB access in do_compute_shiftstate()
The size of individual keymap in drivers/tty/vt/keyboard.c is NR_KEYS, which is currently 256, whereas number of keys/buttons in input device (and therefor in key_down) is much larger - KEY_CNT - 768, and that can cause out-of-bound access when we do sym = U(key_maps[0][k]); with large 'k'. To fix it we should not attempt iterating beyond smaller of NR_KEYS and KEY_CNT. Also while at it let's switch to for_each_set_bit() instead of open-coding it. Reported-by: Sasha Levin <sasha.levin@oracle.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/tty/vt/keyboard.c30
1 files changed, 9 insertions, 21 deletions
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index f973bfc..1e93a37 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -366,34 +366,22 @@ static void to_utf8(struct vc_data *vc, uint c)
static void do_compute_shiftstate(void)
{
- unsigned int i, j, k, sym, val;
+ unsigned int k, sym, val;
shift_state = 0;
memset(shift_down, 0, sizeof(shift_down));
- for (i = 0; i < ARRAY_SIZE(key_down); i++) {
-
- if (!key_down[i])
+ for_each_set_bit(k, key_down, min(NR_KEYS, KEY_CNT)) {
+ sym = U(key_maps[0][k]);
+ if (KTYP(sym) != KT_SHIFT && KTYP(sym) != KT_SLOCK)
continue;
- k = i * BITS_PER_LONG;
-
- for (j = 0; j < BITS_PER_LONG; j++, k++) {
-
- if (!test_bit(k, key_down))
- continue;
+ val = KVAL(sym);
+ if (val == KVAL(K_CAPSSHIFT))
+ val = KVAL(K_SHIFT);
- sym = U(key_maps[0][k]);
- if (KTYP(sym) != KT_SHIFT && KTYP(sym) != KT_SLOCK)
- continue;
-
- val = KVAL(sym);
- if (val == KVAL(K_CAPSSHIFT))
- val = KVAL(K_SHIFT);
-
- shift_down[val]++;
- shift_state |= (1 << val);
- }
+ shift_down[val]++;
+ shift_state |= BIT(val);
}
}